1. Field of the Invention
The present invention relates to a semiconductor device having an optical waveguide for performing an optical communication, and a method of detecting light therefor.
2. Description of Related Art
An attempt such that an optical waveguide is formed on a silicon substrate to implement any optical communication capabilities has been recently noted because this enables an optical substrate and an electric substrate to be combined to one chip or an existing manufacturing line for silicon such as a manufacturing line for complementary metal-oxide semiconductor (CMOS) can be utilized, or the like.
Silicon material has transparency on light having a wavelength of 1100 nm or more. This transparency enables light having a band of 1300 nm or 1550 nm, which is used for an optical communication of main line system, to be guided into an optical waveguide, so that the silicon material has been hoped as optical communication parts for which the light having any of these wavelengths is used. In order for the silicon material to be used as the optical communication parts, various kinds of studies for wavelength filter parts, optical amplifier parts, etc. have been carried out.
If a photoreceptor is formed on the silicon substrate, it is necessary to form another material thereon because the silicon material has transparency on light having a wavelength of 1100 nm or more. Thus, a photoreceptor has been often studied in which germanium (Ge) is mainly used as light-absorbing material (see an article, “Increasing penetration of optical transmission into a case of deice: Precedence by a rooter or a portable telephone” of NIKKEI ELECTRONICS published on Jun. 6, 2005, by Tesuo NOZAWA, pages 59 through 70 and FIG. 11 thereof).